Motor-controller.



H.'F. EL SHOFF. MOTOR CONTROLLER. AgrLmA Tlon FILED .'I UNE so, 1006.

Patented Oct. 27,1908.

INVENTOR WITNES s55 citizen of the United N1TED STAT is AT ;EENRY ELSHOFF, OF NORWOOD, OHIO, ASSIGNOR TO ALLIS-OHALMERS COMPANY, A (lOR-enrich.

PORATION OF NEW JERSEY, AND THE BULLOCK ELECTRIC MANUFACTURING COMPANY,

' A oonronn'rlon oronio.

moron-commence.

Patented Oct. 27, 1908.

implication filed June 30, 1906. Serial No. 324,175.

To all whom it may concern:.

Be it known that I, HENRY Ff ELsHoFF,

States, residing at Nor- 1 wood, in the county of Hamilton and State ofOhio, have invented certain new and useful Improvements inMotor-Controllers, of which the following is a full, clear, and ex actspecification.

My invention relates to controllers.

In the patent to Dunn No. 797,271, granted Aug. 15, 1905, there isdescribed a multiple-voltage controller in which afixed resistance istemporarily out into the arms.- ture circuit whenever the connections ofthe armature are changed from one set of mains to another. Thisresistance, now com-- mcnly known as a butler resistance, serves toprevent excessive surges of current through the armature when theimpressed Volta e thereon is either increased. or decreased. %n the Dunnatent this buffer resistance is in-v sorted in circuit by raising one ofthe'contact fingers from the controller drum, thereby.

ggening a short-circuit around the resistance. iis is found to beunsatisfactory, because of the double movement of the drum and thefinger and because there is only a point or line contact between thefinger and its co" crating contact segment on the drum. The presentinvention is intended to overcome this difliculty by having the bufferresistance insorted by a switch so arate from the controller drum. andits fingers, ut operated hy thedrum in its rotation. l

one aspect my invention comprises a controller consisting of a rotatabledrum and a switch arranged to be 0 )ened by said drum when the latter smove between certam positions, together with means which tends closesaid switch and clockwork. mechanism ror retarding such closing.

ln s more specific aspect my invention comprises, in combination, amultiple-voltage controil er, a motor controlled thereby, a resistancein the armature circuit of said motor, a switch normally closed toehortcircuit said resistance, said switch from the controller drum butarrange to he opened thereby to break said short-circuit whenever thearmature connections are changed from one set of mains to smother,

and clockwork mechanism for retarding the closing movement of saidswitch.

multiple-voltage eration of the device,

ates. of on its periphery. jections are so located that they engage withbeing crate Other features of my invention will appear hereinafter.

Figure 1 is an elevation of a part of a corn troller embodying myinvention, with the casing partly brolien away in order to Show theoperating mechanism. Fig. 2 is a section on the line 2-2 of Fig. 1. Fig.3 is a diegrammatic view SllOWl g a development of the controller.

In the drawings, 31 is the controller drum operable by theusual handle32.

plicalole to any form of multiple-voltage con:

troller. The controller drum has contact segments 33 arranged tocooperate with the contact fingers 34. to 39 inclusive, to connect Forthe sake of simplicity the connections of the 0033-.

the armature of motor M to different sets of I the mains 0,5, 0 and d.The drum also has a ring 40 and contact segments 41 arranged tocooperate with contact fingers 42 to 48 in elusive to vary theresistance r in the field circuit of motor M. Mounted on the shaft ofthe controller drum is a cam wheel 49, on the peri hery of which rides aroller 50 carried b a lever 51. The cam wheel 49 is shown dove oped inFig. 3, hut in order to show more clearly the opit is shown as it itscam rejections were on its u ese cam mand move roller 50 as the armaturecomicstions are being changed from one set of mains to another. Lever 51is connected to a switch 52 by a rod 53 and link 54. A spring 55 tendsto close theswitch 52 and-hold it closed. The bar 53 is provided withteeth 56 to form a rack, some of these teeth Being cut away, at 57 for apurpose hereinafter explained. Arranged to engage with the teeth 56 is ainion 58. Integral with pinion 58 or otherwise firmly attached theretois a ratchet wheel 59, whose cooperating pawl 60 is on a gear wheel 61mounted to turn on the same axis as the wheels 58 and 59 but not fixedto said wheels. The gearwheel 61 meshes with pinion 62,-ihte rel: orotherwise attached to wheel 63, Wide cooperates with an escape Ipersurface in-- .1

connections are varied,

ment 64. The escapement is provided with a weight in order to slow itsaction. By reason of the pawl and ratchet 59 and 60 the train of gearingor clockwork mechanism retards only the closing movement of the switch52, its movement in the other direction being free or unretarded. Theswitch 52 when closed short-circuits a resistance R in the motorarmature circuit, but when opened breaks the short circuit toeffectively include the resistance in said armature circuit.

When the controller is moved to change the armature connections from oneset of mains to another, the cam projections on cam wheel 49 move lever51 to open the switch 52 and to include the resistance R in the motorarmature circuit. During this opening movement of the switch the teethof rack 56 en age with those of pinion 58 to rotate the wieels 58 and59. Because of the pawl and ratchet 59 and 60, the rest of the clockworkmechanism remains stationar during this opening movement of the switch52 and conse uently does not retard such movement. is soon as the changeof armature connections has been made, the spring 55 begins to expand toforce the switch 52 toward closed position. This movement of the switch,however, is at first retarded by the clockwork mechanism, the amount ofthis retardation depending upon the rapidity with which the escapement64 can operate.

When the switch is nearly closed, the teeth 56 pass out of engagementwith pinion 58, bringing the cutaway ortion of rod 53 adjacent saidpinion. his allows the final closin movement of switch 52 to beunretarded so that a quick engagement of the switch contacts may besecured. In the controller shown the resistance R is included in circuitwhen the controller passes between positions 7 and 8,14 and 15, 18 and19, 21 and 22, and 23 and 24, and also when it passes to or fron1 o1fposition. Between the positions just mentioned the armature connectionsare changed from one set of mains to another. Between any other twoadjacent positions the controller merely varies the resistance r in thefield circuit of the motor. This field resistance is arranged to beincreased as the controller is moved forward between those adjacent.positions where the armature connections are not varied, thus increasingthe speed of the motor, but to be cut out whenever the armature thusinsuring a strong field whenever a higher voltage is imvaried asdesired, and

pressed on the armature. I'l desired, instead of having some of theteeth on the rack 56 cut away, one or more of the teeth on pinion 58 maybe cut away.

It is obvious that the part of the controller which controls the fieldresistance may be that the part which controls the armature connectionsmay be adapted to any multiple-voltage system and arranged if desired toreverse the armature current. These modifications as well as many otherswhich readily occur to one skilled in the art may be made withoutdeparting from the spirit of my invention, and are intended to becovered by the following claims.

What I claim as new is:-

1. In a controller, a rotatable drum, a switch biased toward closedposition but arranged to be 0 ened by said drum when the latter is moved)ctween certain positions, and clockwork mechanism for retarding part ofthe closing movement of said switch only.

2. In a controller, a rotatable drum, a switch arranged to be opened bysaid drum when the latter is moved between certain positions, meanswhich tends to close said switch, and clockwork mechanism arranged toretard the first art of the closing movement of said switch but to allowthe last part of the closing movement and all of the opening movementthereof to be unretarded.

3. A multiple-voltage controller, a motor controlled thereby, aresistance in the armature circuit of said motor, a switch normallyclosed to short-circuit said resistance, said switch being separate fromthe controller drum but arranged to be opened thereby to break saidshort-circuit whenever the armature connections are changed from one setof mains to another, and a train of gearin with an escapement forretarding the c osing movement of said switch. 1 I

4. A multiple-voltage controller, a motor controlled thereby, aresistance for the armature circuit of said motor, a switch normallyclosed to short-circuitsaid resistance, said switch being, separate fromthe controller drum but arranged to be opened thereby to include saidresistance in the armature circuit whenever the armature connections arechanged from one set of mains to another, means tending to close saidswitch, and a clockwork escapement for retarding such closure.

5. A n1ultiplevoltage controller, a motor controlled thereby, aresistance for the armature circuit of said motor, a switch normallyclosed to short-circuit said resistance, said switchbeing separate fromthe controller drum but arranged to be opened thereby to effectivelyinclude said resistance in the armature circuit whenever the armatureconnections are changed from one set of mains to another, means tendingto close said switch, and clockwork mechanism for retarding suchclosure, but arranged to allow a free opening movement of the switch.

6. A multiple-voltage controller, a motor, controlled thereby, aresistance in the armature circuit of said motor, a switch normallyclosed to short-circuit said resistance, said switch being separate fromthe controller drum but arranged to be operated thereby to,

open said short-circuit whenever the arma-, ture connections are changedfrom one set of; mains to another, and clockwork mechanlsm for retardingpart of the closing movement of said sw tch. V

7. A multiple-voltage controller, a motor controlled thereby, aresistance in the armature circuit of said motor, a switch normallyclosed to short-circuit said resistance, said switch being separate fromthe controller drum but arranged to be operated thereby to open saidshort-circuit whenever the annature connections are changed from one setoi' mains toanother, and clockwork mechan- 'drum but arranged to beeened thereby to include said resistance in t e armature circuit wheneverthe armature connections are changed from o'ne'set of menus to another,

' means tending to close said switch, and clockwork mechanism forretarding such closure while allowing a free opening movement of I.

the switch.

9. In a motor control system, multiplevoltage mains, amotor, a drumcontroller for connecting the motor armature to different sets of themains, a resistance in the armature circuit of the motor, a switchseparate from thecontroller and biased to closed position toshort-circuit said resistance, means whereby a movement of thecontroller between certain positions opens said switch, and clockworkmechanism for retarding theclosure of said switch.

In testimony whereof in the presence of two witnesses. i

' HENRY F. ELSHOFF. Witnesses:

GEO. B. SoHLEY, FRED J KINSEY.

